There's also the JET method that is worth at least knowing (I don't ever use it, though). With those "keywords" in mind, a search should give you a very brief overview of what they are.
Very brief summaries:
One Piece: One long length of string, which results in two knots.
Two Piece: Two pieces of string, one for M, one for X: Results in 4 knots
Proportional: Tension changes with the length of string, outside is looser. Supposedly expands the sweetspot, reduces jarring on off center strokes.
Box: Sort of like ATW, except you make a box pattern on the frame (http://www.stringerspad.com/atwqbox.html
JET: Combination of Proportional and Box (like I said, simplified summary). IMHO largely marketing.
If you want to know more than a simple summary, start using that search function, OR google (keyword site:tt.tennis-warehouse.com). I'm assuming you're not really a stringer due to your question, so if you have any specific questions about the process and how they relate to the above, please ask (specific) questions. I won't speak for everyone, but the impression I get is the techniques forum isn't really all about the traditional spoon feeding that you might get elsewhere.